Moistureproof material



3 positions were Patented Oct. 5, 1937 mors'ruanraoor MATERIAL Arioe R. Olsen, Wilmington, Del, .assignor to I Hercules Powder Company, Wilmington, Del, a corporation of Delaware N0 Drawing.

11 Claims.

This invention relates to a moistureproof material, and more particularly to a moistureprooi materialcomprising a base of cellulosic material,

preferably transparent sheet cellulosic material, 5 as, for example, glassine paper, regenerated cellulose, etc., or of other transparent sheet material, as, for example, a cellulose ester or ether, gelatin, agar-agar, etc., coated with a moisture-proofing composition comprising chlorinated rubber and an abietyl or hydrogenated abietyl. compound, preferably one which will act as a plasticizer or fiexilizer for the chlorinated rubber.

The term moistureproof, as understood by the art and as used in this specification, describes a coated base material which has a moisture permeability of, at most, one-tenth of the moisture permeability of the uncoated base material employed in its production, and also describes a coating composition capable of producing this re- 20 duction in moisture permeability when applied to a base material in a relatively thin coating, of, for example, in a weight coating of from 2 to 5 'pounds per 3000 square feet of base material.

Heretofore it has been considered impossible to produce a composition capable of moistureproofing these base materials without the inclusion of a wax or waxy material in the moistureprooflng composition. In fact it has always been thought that the moistureproofing qualities of these comdue almost entirely to their wax content.

The inclusion of wax in various types of coating compositions in order to give them a moistureprooflng character has produced many difflculties in the application of such coatings to base materials not encountered in the application of waxfree compositions. These difficulties have arisen particularly in the drying of the moistureproofing compositions, but have been regarded as caused by unavoidable characteristics inherent in moistureproofing compositions.

Now in accordance with this invention it has been found that an improved moistureproof ma-' terial may be produced by coating a base. mapreferably transparent, as glassine, regenerated cellulose, etc., cellulose esters and ethers, gelatine, agar-agar, etc., in sheet form, etc., with a moistureproof composition comprising chlorinated rubber and an abietyl or hydrogenatedabietyl compound, preferably one capable of plasticizing the chlorinated rubber, as, for example, methyl abietate, ethyl abietate, amyl abietate, hydrogenated methyl abietate, hydroterial, as,'for example, sheet cellulosic material,

genated ethyl abietate,- hydrogenated 'ainyl Application February 1, 1935,

abietate, abietyl alcohol, hydrogenated abietyl a'lcohohabietyl stearate, etc. Where-the flexibility of the moistureprooi' coating is notof great importance, non-plasticizing abietyl or hydrogenated abietyl compounds, as, for example, 5 abietic acid, glyceryl abietate, etc., may be used.

For producing the moistureproof material in accordance with this invention the coating compositions including chlorinated rubber and various hydrogenated or unhydrogenated abietic 10, acid esters described in U. S. Patent No. 1,957;- 786, to William Koch, dated May 8, 1934, may be used, but it will be understood that the present invention is not limited to moistureproof materials produced by the use of such compositions. 15

The chlorinated rubber for use'in the moistureproofing composition in accordance with this invention may be produced by the chlorination of raw or vulcanized rubber by any of the processes generally used in its production.- Desirably, the

chlorinated rubber employed will have a chlorine content, of from about 60 to about 68%, altho any chlorinated rubber having a chlorine content of 50% or more may be used. The viscosity characteristics of the chlorinated rubber employed may vary widely and will be selected with 1 a view-to the desired viscosity and chlorinated rubber content of the moistureproofing composition.

Any abietyl or hydrogenated abietyl compound, but preferably one that has a plasticizing action on chlorinated rubber, may be used in formulating the molstureprooflng composition in accordance with this invention. The following compounds are examples of such materials: methyl abietate, ethyl abietate, amyl abietate, hydrogenated methyl abietate, hydrogenated ethyl abietate, hydrogenated amyl abietate, abietyl alcohol, hydrogenated abietyl alcohol, abietyl stearate, etc.

Whilethere is no diilerence in their moistureproofing action, it is preferable to use hydrogenated abietyl compounds rather-than the unhydrogenated, since the latter are less stable and discolor on prolonged exposure'to light. It will be understood, however, that the use of both'types of compounds is contemplated in the present invention.

The exact formulation of the chlorinated rubber coating composition to be used in any given case will depend upon the flexibility desired, the

flexibility. when using the same proportion of different abietyl compounds, diflerent flexibilities and moisture permeabilities will be produced. In other words, the eflect of various of the abietyl compounds on moisture permeability and fiexibility is not the same.

Preferably the abietyl compound or hydro genated abietyl compound will be included in the moistureproofing composition in amount constituting from about 40% to about 80% by weight of the amount of chlorinated rubber present.

The most desirable amount of such abietyl comfas .ot the solution used will depend upon 5 It is, oi. course,

P unds has been found to be from about 50% to about 60% by weight of the chlorinated rubber content.

The following table shows typical moistureprooflng compositions in accordance with this invention. The permeability values are for glasslne paper coated with a coating of 3 lbs.per 3000 square feet or the respective compositions:

Moisture roofing composition (non-v atile constituents) Moisture. permeability value (grams/sq. meter 24hours) 10 pats chlorinated rubber-c parts amyl able- 10. parts chlorinated rubber-6 parts abietyl aflmratn 10 parts chlorinated rubber-0 parts hydro genated abietylalcohol 10 parts chlorinated rubber-0 parts hydrogenated methyl abietate.

The above permeability values are directly comparable with a permeability of 300-400 for uncoated glassine paper; 108 l-lb. coating) for glassine coated with unplasticized chlorinated rubber; 127 (4 lb. coating) for glassine coated with a composition comprising 10 parts chlorinated' rubber and 4 parts tricresyl phosphate; and 101 for glassine coated (4 lb. coating). with a composition comprising 10 parts chlorinated rubber and 3 parts dibutyl phthalate.

in any given case will be obvious to those skilledin the art. The viscosity ofthe solution used will depend on its total solids concentration and on the viscosity type of chlorinated rubber used.

obvious that given viscosity the higher the solids content oi the solution the thicker will be the film applied, and hence the more moistureproot the finished article. It will likewise be obvious that to obtainan increased solids'content at to use a chlorinype. hasbeen toundin many casestobedesirable ior ease of appl cation and production of a suitably thick coating, but this may be varied widely and is not, or course, in any way critical.

The thickness applied to the base material mustbe sumcient to 75 produce a sufiiciently low permeability value. but.

Iorth, are defined as for a solution of a a given solution with a transparent chlorinated in most cases, not such as to impair the transparency oi the finished product. A coating of 2 to 5 pounds per 3000 square'feet of base material is adequate-for inoistureprooiness and will noti impair the transparency of the coated materia I Abietyl compounds, as specification and in the claims hereinafter set compounds, the latter compounds being specifically characterized as hydrogenated abietyl compounds.

What I claim and desire to protect by Letters Patent is:

l. A flexible, transparent, moistureproof sheet comprising a sheet of transparent cellulosic material selected from the group consisting of glassine paper and regenerated cellulose coated with a transparent chlorinated rubber film containing a compound having the hydrocarbon nucleus of abietic acid in amount sufilcient-to produce a moistureprooi film but insufilcient to impair the transparency of the film.

2. A flexible, transparent, moistureprooi material comprising a sheet of regenerated cellulose coated with a-transparent chlorinated rubber film containing a compound having the hydrocarbon nucleus of abietic acid in amount suificient to produce a moistureproo! film but insufficient to impair the transparency of the film.

3. A flexible, transparent, 'moistureproof material comprising a sheet of glassine paper coated with a transparent chlorinated rubber film containing a compound having the hydrocarbon nucleus or abietic acid in amount sufilcient to produce a moistureproof film but insufilcient to impair the transparencyoi the film.

4. A flexible, transparent, moistureproot sheet comprising a sheet of transparent cellulosic material selected from the group consisting of ,glasslne paper and regenerated cellulose coated with a transparent chlorinated rubber film containing a compound having the hydrocarbon nucleus or abietic acid and capable of plasticlzing chlorinated rubber in amount sufilclent to produce a moistureprooi film but insufilcient to impair the transparency of the film.

5. A flexible, transparent, moistureproo! sheet comprising a sheet of transparent cellulodc material selected from the groupconsisting of glassine paper and regenerated cellulose coated with a transparent chlorinated rubber film containing a com d having the hydrocarbon nucleus of hydroabietic acid in amount sufilcient to produce a moistureprooif film but insuificient to impair the transparency of the film.

6. A'flexible, transparent, moisturepl'oof sheet comprising a sheet of transparent cellulosic material selected from the group consisting ct glassine paper and regenerated cellulose coated with a transparent chlorinated rubber film containing a compound having the hydrocarbon nucleus of hydroabietic acid and r M of plasticizing chlorinated rubber in amount sufilcient to produce a moistureproot film but insufiicientto impair the transparency of the film.

'1. A flexible. transparent, moistureproot sheet a sheet of terial selected from the group consisting or paper and regenerated cellulose coated rubber film cmtaining' hydrogenated methyl abietatein amount sufiicientto produce a moistureproof film but the term is used in this compounds containing the carbon skeleton of the hydrocarbon nucleus of abietic acid, and include hydrogenated abietyl insuflicient to impair the transparency of the film.

8. A flexible, transparent, moistureproof sheet comprising a sheet of transparent celluloslc ma- 5 terial selected from the group consisting of glassine paper and regenerated cellulose coated with a transparent chlorinated rubber film containing abietyl stearate in amount suflicient to glassine paper and regenerated cellulose coated with a transparent chlorinated rubber film containing a compound having the hydrocarbon nucleus of abietic acid and capable of plasticizing chlorinated rubber in amount of from about 40% 5 to about 80% by weight of the chlorinated rubber.

11. A flexible, transparent, moistureproof sheet comprising a sheet of transparent cellulosic material selected from the group consisting of glassine paper and regenerated cellulose coated with a transparent chlorinated rubber film containing a compound selected from the group consisting of abieticacid esters, abietyl alcohol,

abietyl alcohol esters, hydrogenated abietic acid esters; hydrogenated abietyl alcohol and hydrogenated abietyl alcohol esters, in amount suflicient to produce a moistureproof film but insufflcient to impair the transparency of the film.

. go ART-DE R. DISEN. 

